Members of the Northern Ireland Institute of Agricultural Science (NIIAS) visited the salt mines at Carrickfergus in Co. Antrim earlier this week.
The operation, which is owned by the Irish Salt Mining and Exploration Company Ltd, provides road-de-icing grit, used across the island of Ireland, Scotland and other parts of the UK. It employs 60 people.
Salt licks, sold in one-tonne tote bags, are also made available to agricultural merchants and individual farmers.
However, the vast bulk of the mines’ output is used for winter gritting operations with local councils and road maintenance companies the main customers for the product.
Commercial mining has taken place at the east Antrim site for almost 60 years. The operation commenced close to the coastal village of Kilroot, but has since pushed northwards in the general direction of Ballycarry, some five miles north of Carrickfergus.
All of the mining takes place underground, with the current extraction operations taking place some 500m below the surface.
The salt is blasted-out using commercial explosives. It is crushed at a number of locations and then brought to the surface using conveyors.
The mining operation taps into a seam of salt that extends westwards across the Irish Sea into the north of England and beyond that into mainland Europe.
Mine manager, Jason Hopps, hosted the NIIAS tour. He confirmed that 500,000t of salt are produced at Carrickfergus on an annual basis.
He outlined: “The blasting and crushing operations take place throughout the year, with salt stock piled so as to ensure that we can meet those periods of high demand during the winter months.
“We have long-term contracts with customers, which entrails us both producing the salt grit and delivering the product to their stores at a range of locations.
“Rock salt is a commodity product, and demand fluctuates from one year to the next, depending on the severity of the weather during the winter months.
“The business is extremely energy intensive – this is why we plan to develop a solar farm on lands adjacent to the mining operation in the very near future.”
The salt seams at Carrickfergus are extremely stable. They are equivalent to 40 newton concrete in terms of their physical strength.
“We leave an extensive arrangement of salt pillars in situ. These provide the levels of physical stability and safety, which underpin the entire mining operation,” Hopps added.
